a) Conventional Thermal Power Plants:
There are many types of conventional thermal power plants, most of which convert thermal energy to fluid energy to mechanical energy to electrical energy. The principal sources of electrical power convert thermal energy generated by burning coal or gas or by atomic fission to superheated steam—working fluid—which is then converted to rotary mechanical power through a turbine which, in turn, drives an electro-mechanical generator.
b) Alternative Renewable Power Generation Systems:
There are well known also alternative natural renewable energy sources in contrast to energy generated from fossil fuels, from which is possible also to generate electricity, as for example are: the sun radiation by photovoltaic panels; the wind by wind turbines; the heat stored in the interior of the Earth by geothermal plants; or the rainwater when descending through rivers or when is harnessed in dams by hydropower plants; the seas as thermal masses by sea thermal energy conversion plants—OTEC, tidal and current in oceans by water reaction turbines, and wave power by buoys per example.
It has also been proposed to use a closed loop ferrofluid system to drive a turbine for generation of power. In such a system, ferrofluids, which undergo large changes in their magnetic properties with temperature, are subjected to heating and cooling at separate points of the closed loop so that, by use of an electromagnet, a self-pumping action can be created which may be used to drive the turbine. There are several prior-art devices dealing with this matter. Namely, a ferrofluid electrical generator is disclosed at U.S. Pat. No. 4,064,409, entitled “Ferrofluidic Electrical Generator” by Charles M. Redman, and U.S. 2006/0110262 A1, entitled “Device Of Micro Loop Thermosyphon For Ferrofluid Power Generator”, by Li-Chieh.
In order to a better understanding of some aspects of this disclosure Ocean Thermal Energy Conversion plants—OTEC, will be described with greater detail below:
The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, seas and land masses. Earth's land surface, seas and atmosphere absorb solar radiation, and this raises their temperature. Sunlight absorbed by the seas and land masses keeps the surface at an average temperature of 14° C. The total solar energy absorbed by Earth's atmosphere, seas and land masses is approximately 3,850,000 exajoules (EJ) per year. The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined. Tropical oceans encircle Earth in an equatorial band between the Tropic of Cancer (23.5° North latitude) and the Tropic of Capricorn (23.5° South latitude). Much of that critical solar radiation initially falls on the tropics, where the Sun lies almost directly overhead for the entire year. The water temperature of tropical oceans thus typically exceeds 20° C. (68° F.) and stays relatively constant throughout the year.
Sea Thermal Energy Conversion plants—OTEC, was first described by French scientist A. d'Arsonval in 1881, aims to produce electricity by utilizing an essentially inexhaustible energy supply (the sun), a vast heat store (the surface region of the seas), and a large capacity heat sink (a deep region of the sea). A typical OTEC electrical power plant as described in the modern literature comprises a closed-loop thermodynamic system through which a working fluid (e.g., ammonia), which vaporizes at the temperature of the sea surface, is circulated from an evaporator to a turbine, from the turbine to a condenser, and from the condenser back to the evaporator for the recirculation through the system. The working fluid enters the evaporator in liquid phase, and is vaporized in the evaporator, which is immersed in relatively warm water drawn from the surface region of the sea. The vaporized working fluid then passes to the turbine and gives up energy to the turbine, which drives an electrical generator. The working fluid exhausted by the turbine then passes to the condenser, which is maintained at the temperature of cold water drawn from a deep region of the sea. Condensation of the working fluid to liquid phase occurs in the condenser. The condensed working fluid is thereupon pumped back to the evaporator to repeat the cycle.
Different samples of Ocean Thermal Energy Conversion plants are disclosed in: U.S. Pat. No. 1,952,520 to Kenneth M. Urquhart; U.S. Pat. No. 2,006,985 to Georges Claude and Paul Boucherot (Mr. Claude was d'Arsonval's student, being Mr. Claude who actually built the first OTEC plant, in Cuba in 1930, being capable the system to generate 22 kW of electricity with a low-pressure turbine); U.S. Pat. No. 2,595,164 to Leon Nisolle; U.S. Pat. No. 3,312,054 to James H. Anderson and J. Hilbert Anderson Jr.; U.S. Pat. No. 3,805,515 to Clarence Zener; U.S. Pat. No. 3,896,622 to George T. Daniello; U.S. Pat. No. 3,967,449 and U.S. Pat. No. 6,202,417 to Earl J. Beck; U.S. Pat. No. 4,083,189 to John G. Fetkovich; U.S. Pat. No. 4,087,975 to Lester J. Owens, assigned to the National Aeronautics and Space Administration—NASA of the USA; U.S. Pat. No. 4,186,311, U.S. Pat. No. 4,200,807, and U.S. Pat. No. 4,302,297 to A Gerald F. Humiston; U.S. Pat. No. 4,189,647 and U.S. Pat. No. 4,210,820 to J. Michael Wittig; U.S. Pat. No. 4,189,924 to Bernard L. LaCoste; U.S. Pat. No. 4,441,321 to Stuart L. Ridgway. And more recently in US 2009/0260358 to Lance Greer; US 2009/0217664 and US2010/0139272 to Robert James Howard, et. al.
Further details regarding OTEC systems are provided in an article entitled “Engineering Aspects of OTEC Systems”, by Lloyd C. Trimble, published by the Society of Naval Architects and Marine Engineers in the Proceedings of the Spring Meeting in San Francisco, Calif., on May 25-27, 1977. Prototype OTEC electrical power plants have been built in Hawaii and in Nauru to demonstrate feasibility. To date, however, full-scale OTEC electrical power plants have not been built.
There are other methods of thermal energy conversion for power generation that had not been commercially build, but that had been for over a century extensively studied and considered, where the hydropower system from the rain cycle in nature is somehow imitated. In those methods the energy is obtained from the convective flow of a working fluid through an open or closed circuit, wherein said liquefied working fluid gasifies in an evaporator unit located at the lower level of said circuit, by gaining heat from a heat source; ascending gasified the working fluid to an upper level through an ascending conduit, increasing its potential energy; liquefying said working fluid in a condenser unit located at said upper level by giving heat to a heat sink; descending the liquefied working fluid because the force of gravity through a descending conduit, and driving a power extraction apparatus that is connected to said descending conduit, which is commonly a rotary engine, as per example a turbine, that in turn drives an electric generator; returning then such liquefied working fluid to the environment when is an open cycle, or to the lower initial level of said circuit when is a closed circuit, and restarting the cycle.
Several of these methods had been disclosed in the following patents, that are chronologically cited: U.S. Pat. No. 196,759 to Thomas M. Miller; DE 361,473 to Ernst Wiefel; U.S. Pat. No. 1,544,029 to Hans J. Nelson; U.S. Pat. No. 2,636,129 to Edward A. Agnew; U.S. Pat. No. 3,140,986 to Walter A. Hubbard; U.S. Pat. No. 3,338,797 to Nicolai T. Hermansen; U.S. Pat. No. 3,375,664 to William M. Wells, wherein the invention described was made in the course of, or under, Contract No. W-7405-ENG-48 with the United Sates Atomic Energy Commission; U.S. Pat. No. 3,414,481 to Hebert C. Kelly, Jr.; DE U.S. Pat. No. 2,362,138 to Werner Foppe; U.S. Pat. No. 3,953,971 to Sidney A. Parker; U.S. Pat. No. 4,095,429 to Robert E. Morey; U.S. Pat. No. 4,187,686 to Lorenzo A. Pommier; U.S. Pat. No. 4,192,145 to Seiyo Tanaka; U.S. Pat. No. 4,244,189 to Emmanuel Bliamptis; U.S. Pat. No. 4,450,689 to Moe, Per, H.; U.S. Pat. No. 4,255,933 to Wayne Bailey; U.S. Pat. No. 4,280,328—to Claude J. Falconer; U.S. Pat. No. 4,306,416 to Joseph Iozzi; U.S. Pat. No. 4,318,275 to Melvin H. Brown; U.S. Pat. No. 4,382,365 to Gene S. Kira et. al.; U.S. Pat. No. 4,391,100 to Derrick A. Smith; U.S. Pat. No. 4,760,706 to Gamal E. Nasser; U.S. Pat. No. 5,488,828 to Pierre Brossard; U.S. Pat. No. 6,434,942 to Walter T. Charlton; U.S. Pat. No. 6,651,434 to Sanchez Gomez, Gines; and US 2010/0077750 to Anthony Russo.